1. Technical Field
The present invention relates to an image-forming apparatus and an image-forming process.
2. Related Art
In conventional electrophotographic color-image recording devices, images in basic three primary colors are developed respectively according to image information, and these toner images are stacked one by one for obtaining a color image. Specifically, the following apparatus structures are known: so-called four-cycle machines that form a color image by developing a toner image in each color on a photosensitive drum carrying a latent image formed by an image-forming method and repeating transfer of the toner image in each color onto a transfer member; and tandem machines which have image-forming units in the respective colors each having a photosensitive drum and a developing device and which obtain a color image by transferring the toner images onto a traveling transfer member one by one.
These machines are common at least in that they have multiple developing devices for different colors. Accordingly, four developing devices for three primary colors and black are necessary for usual color image formation. In the tandem machines, it is necessary to provide four photosensitive drums corresponding to four developing devices and also a means for synchronizing the four image-forming units; therefore, increase in the size of the machines and in the cost is inevitable.